Conventionally, there has been provided a cooking device of a hot-air circulation type capable of two-stage cooking with two trays set up in a heating chamber (see, e.g., JP 2011-21864 A (PTL1)).
Unfortunately, this cooking device has a drawback that since hot air circulates in the whole heating chamber in either one-stage cooking or two-stage cooking, even one-stage cooking of smaller food quantities involves heating time nearly equal to that for two-stage cooking, making it impossible to shorten the heating time of one-stage cooking.
Accordingly, it is conceivable that in a cooking device capable of two-stage cooking, for the purpose of shortening the heating time for one-stage cooking than for two-stage cooking by efficiently circulating a heating medium during the one-stage cooking, a damper is provided on the circulation path of the heating medium so that an upper blowoff hole for blowoff to an upper region in the heating chamber is opened and closed by the damper.
In this case, however, the circulation path comes to high temperatures of 100° C. or higher due to the flow of a high-temperature heating medium inside the path. Therefore, the damper itself provided in the circulation path also comes to high temperatures. This involves a need that a motor for opening and closing the damper be installed at a position apart from the damper, making it difficult to make up a compact opening/closing mechanism. Thus, the mounting position of the opening/closing mechanism is varied among individual cooking devices, causing a difficulty in fulfilling secure opening/closing operations, as a problem.
Also, packings are needed to reduce collision noise against the circulation path or a wall surface of the heating chamber upon opening and closing of the damper or to close the upper blowoff hole. However, because the damper comes to high temperatures and high humidities as described above, rubber or other packings cannot be used as another problem.